This invention relates to a fastener gun for driving a fastener.
Fastener guns are known in the art and include a handle pivotally attached to a fastener gun housing. Rotating the handle toward the fastener housing biases a power spring. A user's hand, received on an end of the handle remote from the pivot, rotates the handle toward the fastener gun housing. Releasing the biased power spring moves a plunger to drive a fastener into a workpiece.
Increasing the power spring's force allows a user to drive larger fasteners into a workpiece. However, such a power spring requires increased biasing forces. To increase forces available for biasing, some fastener guns increase the force required to rotate the handle toward the fastener housing. Some users are not able to exert the increased forces. Other users can exert the increased forces, but only through some of the range of handle travel. At some points of handle travel, exerting the increased forces is especially difficult, such as when initiating handle movement or just prior to releasing the power spring. Further, user's hands can exert more force in some positions than in other positions.
To increase biasing forces without increasing the handle forces, some fastener guns increase the handle size. Other fastener guns may increase the handle size to achieve current biasing forces, with reduced efforts. Some users may be unable to effectively maneuver the larger handle due to the user's hand size or other physical limitations. Although increasing the handle size is effective for increasing biasing forces, or lowering efforts while maintaining existing biasing forces, in many applications it is desirable to lower the forces without increasing the handle size.
It would be desirable to increase the forces driving a fastener from a fastener gun while accommodating a user's hand.